Interplanetary dust particles IDPs

In recent years, a new source of information about stellar nucleosynthesis and the history of the elements between their ejection from stars and their incorporation into the solar system has become available. This source is the tiny dust grains that condensed from gas ejected from stars at the end of their lives and that survived unaltered to be incorporated into solar system materials. These presolar grains (Fig. 5.1) originated before the solar system formed and were part of the raw materials for the Sun, the planets, and other solar-system objects. They survived the collapse of the Sun s parent molecular cloud and the formation of the accretion disk and were incorporated essentially unchanged into the parent bodies of the chondritic meteorites. They are found in the fine-grained matrix of the least metamorphosed chondrites and in interplanetary dust particles (IDPs), materials that were not processed by high-temperature events in the solar system. 

We will now describe each of the various kinds of meteoritic samples available for cosmochemical investigation, progressing from primitive materials to samples from differentiated bodies. Presolar grains extracted from meteorites have already been described in Chapter 5, and interplanetary dust particles (IDPs) and returned comet samples will be described in Chapter 12. 

What are interplanetary dust particles (IDPs) made of, and what do they tell us about the... 

Laboratory experiments have shown that radiation processing of simulated presolar ices leads to more complex molecular species [25-27]. Hundreds of new compounds are synthesized, although the starting ices contain only a few simple common interstellar molecules. Many of the compounds formed in these experiments are also present in meteorites and cometary and asteroidal dust (interplanetary dust particles - IDPs), and some are presumably relevant to the origin of life, including amino acids [28,29], quinines [30], and amphiphilic material [31]. 

In addition to meteorites, three other important types of extraterrestrial material are available for analysis interplanetary dust particles (IDPs), micrometeorites, and Stardust samples. Interplanetary dust particles are collected in the stratosphere by high-altitude research aircrafts. Most of these samples are smaller than 20 pm in diameter, although some of the highly porous cluster particles probably exceeded... 

The focus of the chapter is on the smallest range of particle sizes (< 1 cm) and thus the initial phases of dust coagulation in young gas-rich disks, since these are the ones that can be observed in extrasolar systems and have preserved some very early record in chondritic meteorites and interplanetary dust particles (IDPs). 

Many of the micron-sized interplanetary dust particles (IDPs) have approximately chondritic bulk composition (see Chapter 1.26 for details). Porous IDPs match the Cl composition better than nonporous (smooth) IDPs. On an average, IDPs show some enhancement of moderately volatile and volatile elements (see Palme, 2000). Arndt et al. (1996) found similar enrichments in their suite of 44 chondritic particles (average size 17.2 1.2 p.m). The elements chlorine, copper, zinc, gallium, selenium, and rubidium were enriched by factors of 2.2-2.7. In addition, these... 

Interplanetary dust particles (IDPs) are the smallest and most fine-grained meteoritic objects available for laboratory investigation (Figure 1). In contrast to meteorites, IDPs are... 

Molster F. J., Bradley J. P., Sitko M. E., and Nuth J. A. (2001) Astromineralogy the comparison of infrared spectra from astrophysical environments with those from interplanetary dust particles (IDPs). In Lunar Planet Set XXXII, 1391. The Eunar and Planetary Institute, Houston (CD-ROM). 

Although °Th has found widespread use as a CFP, applications are limited by its 75 ka half-life to sediments deposited during the past —300 ka. Paleoceanographic research would clearly benefit from a CFP that can be applied further back in time. Calibration work is underway to determine the suitability of extraterrestrial He, contained in interplanetary dust particles (IDPs), as a CFP that may be applied to much older sediments. 

Most of interplanetary dust particles (IDPs) contain 2-10 % carbon by weight in a variety of physical forms, including amorphous materials with a minor amount of oxygen and nitrogen. Allamandola et al. [27] reported tliat both IDPs and meteorites might contain materials similar to PAHs. Clemett et al. [28] identified many PAHs and their alkylated derivatives in IDPs. 

Interplanetary dust particles IDPs collected in the Earth s stratosphere are of multiple origins. Solar system objects come in anhydrous and hydrated forms. The anhydrous, chondritic-porous group are thought to be the most primitive and least-processed of all matter in the solar system... 

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